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SUPPLEMENTAL NOTE. 
Since that portion of the present work which relates to 
Vegetable Fertilisation was set in type, I have received a copy 
of a very curious paper on the same subject, under the title of 
Beitrdge zurLelire von der Befruclitung derPflanzen; by A. J. C. 
Corda; in which there are many original observations con- 
nected with this most interesting part of Vegetable Physiology. 
The author's observations are chiefly upon the manner in 
which the pollen tubes act upon the ovules of coniferous 
plants, and especially of the Spruce Fir. In these naked 
seeded vegetables it is necessary that a direct communication 
should take place between the pollen grain and the foramen 
of the ovule : for the usual intermediate apparatus of style and 
stigma is wanting. The direction of the pollen tubes was 
found to be through the foramen of the secundine into the 
apex of the nucleus, into which they pierced till they reached 
its very bottom. The author says, — " I saw the pollen tubes 
pass through the foramen of the secundine, enter the mouth 
(embryos tome) of the nucleus, thin away till they reached the 
bottom of the latter, then suddenly contract, and evacuate their 
contents in the form of an opaque matter, which at first is colour- 
less. After this evacuation, the pollen tube remains in the 
foramina of the ovule in the form of a thin, empty, bright tubu- 
lar thread ; and the evacuated matter forthwith fashions itself 
into a bag, which eventually contains the embryo, which 
quickly increases in size, and has often at either end a ragged 
appearance, wrinkled on its surface, and darkened internally. 
It never loses its connection with the pollen tube. While the 
embryo bag is growing, an alteration takes place in the cel- 
lules of the nucleus ; these are at first filled with polygonal 
